A world without chaos.
Such a place sounds absolutely lovely on paper, does it not? No unplanned events, no unexpected inconveniences, no unpredictability. Everything that a pony plans, they'll be able to do without being so much as a minute behind schedule. Surely, for ponies like Twilight, the ones that live and breathe off of organization, that kind of world sounds absolutely perfect for her. However, when chaos actually does disappear due to... things, it becomes very clear to her, and the rest of Equestria, that such a world is not an ideal one. In fact, it's grossly boring.
Fortunately—or unfortunately—there just so happens to be a lovely spirit of chaos who knows exactly what to do: Simply bring the chaos back. Of course, since he himself lacks his chaotic power, he'll need some help from a certain begrudging purple alicorn.
What could possibly go wrong? Neither of them know. After all, what's chaos without a bit of unpredictability?